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Nonmetallic mining and associated activities: Permit MNG490000

The MPCA reissued the General Permit for Construction Sand and Gravel, Aggregate and Hot Mix Asphalt Facilities. Because of changes to the latest version, the permit will retain the same Permit Number (MNG490000), but will be titled "Nonmetallic Mining and Associated Activities."

This webpage is intended to help you determine what type(s) of water quality permit is required at facilities that mine construction sand and gravel; industrial sand; quarry limestone, granite or dimension stone; operate hot mix asphalt production areas; produce concrete block, brick and other products; and/or produce ready-mix concrete. In addition, this Web page provides basic information about the General Permit. A copy of the General Permit is available below:

Step 1. Applicability: do you need a permit?

The General Permit for Nonmetallic Mining and Associated Activities (MNG490000) is a specific type of permit covering both stormwater and wastewater. It is also a multi-site permit, meaning all qualifying sites can be covered with a single permit application. This permit authorizes stormwater discharges to surface waters of the state from the following facilities:

This permit authorizes wastewater discharges from the following activities that do not discharge to surface waters of the state. If there is a surface water discharge, an individual permit is required.

Uncontaminated scale deck wash water that does not use detergents, solvents, or degreasers.

Stormwater and deck wash water collected in holding tanks under scales.

Wash water associated with cleaning of mobile equipment that does not use detergents, solvents, or degreasers.

Waters used for dust control on crushers, conveyors, associated equipment, and site roadways.

This permit authorizes non-stormwater discharges to surface waters of the state. These discharges are the same as those covered under the Industrial Stormwater General Permit (MNR050000).).

Emergency fire-fighting activities.

Fire hydrant and fire suppression system flushing.

Potable water line flushing.

Uncontaminated condensate from air conditioners, coolers, and other compressors and from the outside storage of refrigerated gases or liquids.

Landscape watering provided all pesticides; herbicides and fertilizers have been applied in accordance with manufacturer’s instructions.

Pavement wash waters where no detergents are used and no spills or leaks of potential pollutants such as fertilizers, salts, or toxic and hazardous materials have occurred unless all spilled material has been removed.

Routine external building wash down that does not use detergents, solvents, or degreasers.

Uncontaminated groundwater or spring water.

Foundation or footing drains where flows are not contaminated.

Incident windblown mist from cooling towers that collects on rooftops or adjacent portions of the facility, but not intentional discharges from the cooling tower (e.g., “piped” cooling tower blowdown or drains).

This permit also includes materials approved in Minn. R. 7035.2860 (Beneficial Use of Solid Waste) at sites engaged in activities associated with all SIC Codes listed above. Any recycling and storage of these materials must meet the requirements of Minn. R.7035.2855 (Solid Waste Storage Standards). It also includes associated activities, such as maintenance activities, unless otherwise specified as NOT being covered in the permit (see next section).

Stormwater discharges associated with construction activities from the above sites are also covered under this permit. Therefore, additional coverage under the Construction Stormwater General Permit (MNR100001) is not required.

This permit includes active sites, temporarily inactive sites and inactive sites. Temporarily inactive sites are sites that are not currently undergoing mining or associated activities, but permit coverage is being maintained for the possibility of mining in the foreseeable future. The Permittee must ensure Best Management Practices are in place at temporarily inactive sites. Inactive sites are sites where mining has ceased. Permit coverage can be terminated once the Permittee achieves final stabilization of the inactive site (see Section 2.10 of the permit).

What does this permit NOT cover?

Dewatering of mine or quarry areas other than those under Subsector J1and J2.

Surface water discharges of scrubber or other air emissions control wastewater, cooling or boiler wastewater, floor drains from process areas, equipment/vehicle washing, cleaning and maintenance wastewaters, and sewage.

Mine site dewatering discharges from Subsector J1 and J2 facilities to the following receiving waters:

Prohibited Outstanding Resource Value Waters (ORVW)

Department of Natural Resources (DNR)-designated trout waters.

DNR-posted fish-spawning areas.

If you perform any of these activities above, an Individual NPDES/SDS Permit may be required for discharges to waters of the state. Please contact the MPCA with questions, or visit the water permits and rules page to link to water rules, permits and forms.

Nonmetallic Mining and Associated Activities Compliance Audit

Not sure if you need a permit? The audit is intended to be completed for facilities that conduct any Nonmetallic Mining and Associated Activities that do not have permit coverage and wish to evaluate whether they should have coverage. It can also be used by facilities that have permit coverage to assess if they are compliant with the permit’s requirements.

A second option for coverage is the Industrial Stormwater General Permit (MNR05000). Facilities that don’t have multiple sites may choose to have one site covered under this permit. However, the Industrial Stormwater Permit only covers stormwater and specific non-stormwater discharges. No process wastewaters, like gravel wash water and wastewater from washing of buckets and forms at concrete industries, would be covered. Therefore, this option is not for everyone.

Covering new sites under existing general permit coverage

You’ve acquired a new sand and gravel pit (or stone/asphalt/concrete site). Now what? If your other sites already have permit coverage, you can add the new site to your existing coverage without a permit modification. Instead, additional qualified sites should be added using the Site Inventory Report form, which shall be submitted to the MPCA at least 10 days prior to initiation of land-disturbing activities at the new site or initiation of operation at a previously developed site.

Name change? Need to transfer coverage? All pits have closed and ceased operation? Fill out the Permit Change Request form for any of these changes; use this form to transfer ownership or terminate permit coverage.

The Permittee must meet the water-quality based effluent limits and technology-based effluent limits in Sections 2 and 3. These include specific control measures for both stormwater and wastewater. Control measures, or Best Management Practices (BMPs) can be structural or non-structural. Structural BMPs include physical structures like stabilization ponds, sedimentation basins, vegetative swales, or infiltration devices. Non-structural BMPs include activities, like good housekeeping to control sediment from vehicle tracking.

A Pollution Prevention Plan must be prepared and implemented for each site before the site is covered under the permit. This Plan includes both stormwater and wastewater management. Specific standards for P2 Plans are specified in the General Permit.

A Discharge Monitoring Report (DMR) form is required for each stormwater discharge at a site covered under the General Permit. Stormwater must be sampled twice per year and submitted by January 21 for results from the preceding calendar year (see Section 8.1 to 8.12 of the general permit)

If dewatering occurs, monitoring is required quarterly and a DMR must be submitted by January 21 for results from the preceding calendar year (see Section 8.13 to 8.19 of the general permit).

A monthly inspection by facility-designated personnel at each site is required to ensure that the Plan is being followed, with a minimum of one inspection being conducted during a runoff event. Inspections must be documented.

Design and construction standards for wet scrubber impoundments, if present at hot-mix asphalt facilities, are specified in the General Permit.

You may also visit our Small Business Environmental Assistance Program (SBEAP) web page to find helpful Compliance Calendars. SBEAP has developed these calendars for both the Aggregate Industry (Sand & Gravel) and the Asphalt Industry and reference water as well as air and hazardous waste issues.

Step 4. Fill out the reporting forms

The previous permit required an Annual Report to be submitted. This is being replaced by the Discharge Monitoring Report (DMR) forms. These are facility specific forms.

Stormwater must be sampled twice per year and submitted by January 22 for results from the preceding calendar year. If dewatering occurs at Subsector J1 or J2 facilities, monitoring is required quarterly and a DMR must be submitted by quarterly (by Jan. 22, April 22, July 22 and Oct. 22) for results from the preceding calendar quarter. See Section 8 of the general permit linked above for specifics on monitoring.

The MPCA’s Stormwater Program for Industrial Activity: Steps to Compliance includes a webpage called Step 10: Sampling. Nonmetallic Mining and Associated Activities General Permit does not have ‘benchmark’ sampling like the Industrial Stormwater General Permit, the information you must provide is similar. This web page includes information like when and how to take a sample that you may find helpful.

NEW: If your site contains a 10 year, 24-hour storm event control basin, you may be eligible for a monitoring waiver. To request a waiver in monitoring, you must have a professional engineer construct (for new facilities) or verify (for existing facilities) that the stormwater control device and/or the dewatering control device can contain the volume from a 10 year, 24-hour storm event. Limits must be met, but no monitoring is required.

Step 5. Comply with other (MPCA and non-MPCA) requirements

In addition to the water quality concerns at these types of facilities, other environmental considerations may require additional permitting or oversight by various governmental entities.

Water withdrawals— A Water Appropriation Permit from the Department of Natural Resources may be required if more than 10,000 gallons of water per day or 1 million gallons per year is being withdrawn from a state water (including ground water, as in pit/quarry dewatering).

U.S. Army Corps of Engineers — Activities that involve the discharge of dredged or fill material or excavation within waters and wetlands may require approval of the Corps of Engineers. Such activities could include the construction of access roads or the creation of storage areas and building sites. Also, activities related to the construction of pit dewatering outfall structures and the excavation of water detention/retention ponds within waters and wetlands may require Corps approval. For more information, visit the U.S. Army Corps of Engineers – St. Paul District web page, or call their office at 651-290-5375.

Environmental Review — If a new pit or quarry is started, or an existing one is expanded by 40 acres or more, and the pit will have a mean depth of at least 10 feet during its existence, the project needs to have an Environmental Assessment Worksheet prepared. If the new pit or expansion will cover at least 160 acres, mined to a mean depth of 10 feet or more, an Environmental Impact Statement is needed. For more information on this process, visit the Environmental Review web page.

Fuel and Hazardous Materials Management — When equipment is refueled, maintained or repaired outside the shops, special care must be taken to prevent spills, and to quickly contain and collect accidental spills. Used oil, lubricants, antifreeze, paint, solvents, vehicle cleaning wastes, recovered freon, asbestos, PCBs and shop wastes should be properly contained stored, and recycled or disposed of in compliance with MPCA requirements. For more information on Hazardous Waste requirements and the publications available to help you comply, visit the Hazardous Waste Publications web page.

Tanks — Liquid (including fuel) storage tanks, whether aboveground or underground, need to have effective containment and may need to be approved by the MPCA. For more information on tanks requirements, visit the Tank Compliance and Assistance Program web page.

Air Quality Management — All facilities must meet minimum standards for dust and noise control. Facilities with crushing operations may have to meet additional federal standards for emissions of particulates from processing equipment. It is important to control dust throughout the facility, including at crushers, screens, conveyors and hoppers. The use of fuels, other volatile chemicals, and/or generators may also dictate additional air quality requirements. Depending on production capacity and processing equipment, an Air Emission Permit may be required. For more information, visit the Air Permits and Forms web page{/article.

Solid Waste Management — Some aggregate operations store used asphalt and/or concrete, captured particulate emissions, or other demolition debris. The MPCA encourages recycling of these materials, and of scrap and trash materials, when possible. If this is not practical, used pavement must be disposed of in an approved sanitary or demolition debris landfill. For more information, visit the {article k2:579}Solid Waste web page.

Who to Call

For more information or assistance with water permitting for Nonmetallic Mining and Associated Activities facilities, call Theresa Haugen at 218-316-3920.